| In narrow gap P-GMAW welding, the arc behavior will directly affect the weld forming effect, while the sidewall and current will affect the shape of the arc. The changes of arc shape in the same current pulse period at different time and different current pulse cycles in the same oscillation period in narrow-gap P-GMAW welding are analyzed by high speed photography. The conclusions are as follows: firstly, in narrow gap swing welding, the factors of arc shape change are mainly the size of the pulse current and the distance between the welding torch and the side wall. Secondly, because arc shape and droplet over influence each other, they jointly determine the forming effect of weld, so arc shape is an important factor to determine the welding effect. |